This invention concerns an improved process for preparing ethylene glycol by reaction of oxides of carbon with hydrogen in presence of a catalyst system.
There are ever-increasing efforts to provide new methods of making ethylene glycol particularly useful as a component in polyester fiber and antifreeze formulations. An ever present aim is to prepare said glycol in relatively high yields involving a catalyst system providing good selectivity.
One proposed mode of making ethylene glycol is the reaction of carbon monoxide and hydrogen in presence of variously proposed catalyst systems. The mixture of carbon monoxide and hydrogen, commonly known as synthesis gas, is reacted at elevated pressures and temperatures. For example, in Belgium Pat. No. 793,086 and U.S. Pat. No. 3,940,432 there is described the co-synthesis of methanol and ethylene glycol from mixtures of carbon monoxide and hydrogen using a complex rhodium catalyst. While other metals of group VIII of the Periodic Table have been tested for activity under similar conditions, including cobalt, ruthenium, copper, manganese, iridium and platinum, only cobalt was found to have slight activity. The use of ruthenium compounds in particular failed to produce polyfunctional products such as ethylene glycol. This is illustrated in U.S. Pat. No. 3,833,634 for solutions of triruthenium dodecarbonyl.
This invention therefore is to provide a process of making ethylene glycol by resort to a unique catalyst system which produces said glycol in good yields and selectivity. Other objects will appear hereinafter.